Maximizing Metal–Support Interactions in Pt/Co 3 O 4 Nanocages to Simultaneously Boost Hydrogen Production Activity and Durability

Catalytic hydrolysis of ammonia borane (AB) provides an effective way to generate pure H 2 at ambient temperature for fuel cells. Pt-based catalysts usually exhibit great initial activity toward this reaction but deactivate quickly. Here, we report that the metal–support interactions in Pt/Co 3 O 4 nanocages can simultaneously accelerate the H 2 generation and enhance the catalyst’s stability. The Pt/Co 3 O 4 catalyst is made for the first time by embedding Pt clusters (∼1.2 nm) in a high-surface-area Co 3 O 4 nanocage to maximize the metal–support interface. The turnover frequency of the Pt/Co 3 O 4 catalyst is about nine times higher than that of commercial Pt/C and outperforms almost all other Pt-based catalysts. X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, in situ spectroscopy, and density functional theory calculations suggest that the Co 3 O 4 nanocages with rich oxygen vacancies facilitate the adsorption and dissociation of H 2 O to give electropositive H (H δ+ ), while the in situ embedded Pt clusters can accelerate the formation of electronegative H (H δ− ) from AB. Subsequently, the H δ+ and H δ− spill over to the abundant interfacial sites and bond into H 2 . In addition to this dual-function synergy effect, the strong metal–support electronic interactions between Co 3 O 4 and Pt benefit the desorption of poisonous B-containing byproducts from Pt sites. This effect together with cluster anchoring leads to a fivefold enhancement in durability compared to commercial Pt/C. The metal–support interactions revealed in this study provide more options for catalyst design toward facile H 2 production from chemical hydrogen storage materials.